#define _CRT_SECURE_NO_WARNINGS 1

#include<stdio.h>

int main()
{
    int a = 0;
    int b = 0;
    int c = 0;
    int d = 0;
    scanf("%d %d %d %d", &a, &b, &c, &d);//只返回输入的个数
    int sum = a + b + c + d;
    printf("%d", sum);

    return 0;
}